A few years ago, cattle in an American feedlot went down during transport to a packing plant and others developed severe lameness.
This condition was eventually labelled fatigue cattle syndrome and became a significant animal welfare issue because of the appearance of severely lame, non-ambulatory cattle.
Beta agonists were initially blamed, but numerous studies have essentially proven that it was instead a combination of other factors.
Dr. Dan Thomson of Kansas State University and a team of researchers in production animal medicine identified several stressors that lead to fatigue cattle syndrome (FCS).
This condition can be confused with other syndromes, such as acute laminitis, caused by grain overload, and selenium/vitamin E deficiencies.
FCS symptoms include a strained pattern of breathing and very slow movements leading to non-ambulatory cattle. In severe cases there has been sloughing of the hoofs.
Contributing factors to FCS are possibly preventable. The heat load definitely contributed, considering that the initial cases appeared in temperatures around 35 C.
The findings may lead to specific recommendations in our upcoming Canadian transportation code revision, and we need to be even more careful handling, transporting and butchering cattle in the summer for these reasons.
Depending on distance travelled or the number of cattle moved and sorted, perhaps a maximum temperature will be found that is safe.
We also know that hide colour has a lot to do with heat stress, and these tolerable temperatures may go down as the number of black-hided cattle go up.
I was privy to a very descriptive video showing heat stress in a pen of mainly black- hided cattle. While the majority of the cattle were in the shade of a porosity fence and breathing heavily, the red and white cattle were up at the feed bunk eating.
Of the few cattle I have treated for heat stress over the years, all have been black hided.
Cattle handling, the time taken to load, the distance travelled and the related stress during movement all contribute to FCS.
Until this specific syndrome appeared, there was no reason to suspect we had a problem.
Researchers also performed blood tests, looking at muscle enzyme levels to see if any damage was done. The levels get very high in affected cattle. It is the same with downer cattle as they attempt to rise or calves with white muscle disease.
Thomson and his group found that aggressive handling produced the same muscle lactate levels as running a seven or eight-minute mile or walking for about 20 minutes.
We can all identify with this. If we run too far when we’re not used to it, our muscles can become ex-tremely sore for a few days because of the buildup of lactic acid.
Feedlot cattle are getting bigger, and when they are in prime condition for butchering they are not athletic enough to be running around for any amount of time. The home pen in some large feedlots may be more than a mile from the load-out area, which had a bearing on the incidence of FCS. As a result, changes may need to be made to feedlot design, such as requiring staged moving or adding more load-out areas.
It will be nice to have parameters that are easily measurable and tied in with temperature.
FCS was also found at the packing plants. Common factors contributing to fatigue there were the time the cattle remained in the pens before slaughter and whether shade and cooling were available, particularly in areas with very hot climates.
Density in the pens was another factor because the cattle cannot properly dissipate heat when holding pens are too crowded.
Animal handling practices and facilities were also examined.
Better facilities and staff training can often reduce stress, exertion and rough handling. The type of flooring was also a factor because some floor surfaces can cause injuries to the feet, which starts the process.
In the United States, discovering the causes of FCS has led to a training and monitoring protocol called the FCS Stewardship program. The goal is to minimize or eliminate FCS by removing or reducing these risk factors across the industry.
The incidence of FCS may never have been as high in Canada as in the U.S. because of our more temperate climate, but we still get very hot days in southern parts of the country in summer.
As a result, it makes sense to be aware of the potential ramifications of how we sort, process, load and transport cattle. This is especially true with heavy market weight, black-hided cattle in the hot summer days.
This is also a good example of not jumping to conclusions when emerging diseases come out and thoroughly researching the cause. The feedlot sector was set back when some beta agonists were prohibited from being fed because they were thought to be the cause. We must follow science to allow the cattle industry to progress.